After a tough path to the market, Karyopharm Therapeutics scored a series of FDA approvals for Xpovio in recent years for multiple myeloma and diffuse large B-cell lymphoma. Now, it's looking to take the momentum forward into another cancer indication.
In top-line phase 3 trial results released Tuesday, Karyopharm said Xpovio bested placebo when used as a maintenance therapy for advanced or recurrent endometrial cancer patients who had responded to chemotherapy as a front-line therapy. If approved, the drug would move into an earlier line of treatment as a maintenance therapy, which could give it an enviable market opportunity.
On the SIENDO trial's primary endpoint, patients treated with the Karyopharm drug experienced a median progression-free survival of 5.7 months compared with 3.8 months for those on placebo. That translated to a statistically significant improvement of 50%, the company said.
The study's hazard ratio was 0.7, so in all, the results showed a 30% reduction in the risk of progression or death, the company said. At 12 months, the study showed a 37% increase in the probability that Xpovio patients will be in remission compared with patients on no treatment, Karyopharm added.
The drug was well tolerated and showed no new safety concerns, investigators reported.
Karyopharm Chief Scientific Officer Sharon Shacham, Ph.D., said in a statement the company is "thrilled" with the PFS result "because of what it represents for patients.
"If approved, Xpovio would be the first and only maintenance therapy in advanced or recurrent endometrial cancer, following response to chemotherapy," Shacham added.
While the company celebrated the results, analysts with SVB Leerink are holding out for more info. The team wrote that given "the modest improvement in PFS, we believe questions may remain on whether a 1.9-month benefit will be enough to drive uptake."
Still, in the P53 wild type subgroup, patients' progression-free survival came in at a "considerable" 13.7 months, the SVB Leerink team wrote. That "could provide an opportunity to provide a more targeted benefit.
"We await the full data to better evaluate the opportunity and continue to believe investor focus remains largely on the commercial picture of Xpovio," the analysts added.
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Up next, Karyopharm plans to submit an FDA application based on the data and share the full results at an upcoming medical congress. The biotech aims to complete those tasks during the first half of 2022.
The results came as Karyopharm reported fourth-quarter and full-year 2021 results. During the quarter, the company's product revenues came in just shy of $30 million, a 47% increase from the same period last year. The biotech generated around $98 million in full-year 2021 revenues, a 29% increase from 2020.